<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script>
   //  `typeof`运算符的返回类型为字符串 : undefined、boolean、 string 、 number 、 object 、 function
   // console.log(typeof 1 === 1);// false    'number' === 1
   // console.log(typeof (1===1));// boolean
   // console.log(typeof function(){});// function
   console.log(typeof null);// object
   console.log(typeof []);// object
   console.log(typeof {});// object
</script>
</html>